<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	   <style>
	   	/* 给div中所有的span添加背景颜色——2/3/4  */
			div  span{
				background-color: pink;
			}
			/* 选中2/4两个span */
			div > span{
				 font-weight: bold;
				
			}			
			/* 选中3那个span */
			div > p > span{
			  	/* 字体大小/尺寸 */
					font-size: 2em;
			} 
	   </style>	
	</head>
	<body>
	   <span>1</span>
	  <div>
	  	 <span>2</span>
			<p>
				<span>3</span>
			</p>
			<span>4</span>
	  </div>
	</body>
</html>
